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This study uses more than a decade's worth of data across Arizona to characterize the spatiotemporal distribution, frequency, and source of extreme aerosol events, defined as when the concentration of a species on a particular day exceeds that of the average plus two standard deviations for that given month. Depending on which of eight sites studied, between 5% and 7% of the total days exhibited an extreme aerosol event due to either extreme levels of PM10, PM2.5, and/or fine soil. Grand Canyon exhibited the most extreme event days (120, i.e., 7% of its total days). Fine soil is the pollutant type that most frequently impacted multiple sites at once at an extreme level. PM10, PM2.5, fine soil, non-Asian dust, and Elemental Carbon extreme events occurred most frequently in August. Nearly all Asian dust extreme events occurred between March and June. Extreme Elemental Carbon events have decreased as a function of time with statistical significance, while other pollutant categories did not show any significant change. Extreme events were most frequent for the various pollutant categories on either Wednesday or Thursday, but there was no statistically significant difference in the number of events on any particular day or on weekends versus weekdays. [ABSTRACT FROM AUTHOR]

The Kazhdumi Formation is a significant source of hydrocarbon in the south of Iran, which has produced abundant oil in most onshore oil fields. The hydrocarbon potential of this formation is investigated in 20 fields in the Persian Gulf. total organic carbon contents range from 0.3 to 6% with an average of 1.55%. Most samples have kerogen types II, II/III, and III, which are at the immature to early mature stage. Burial history and thermal maturity investigation show that the Kazhdumi Formation at the Persian Gulf area, in contrast to the Zagros Basin, thermally immature, and poor in terms of hydrocarbon generation. [ABSTRACT FROM AUTHOR]

In this article, by using geochemical methods, the effect of CO2injection effect on the asphaltene precipitation and changing of other oil components was investigated. This study was performed in one of the eastern Persian Gulf oil fields with an API of 30.5. For this subject, gas injection was executed with a slim-tube instrument and minimum miscibility pressure was also measured. An asphaltene precipitation test and liquid column chromatography test were conducted on the oil samples retrieved from the slim-tube instrument. This study indicates that CO2influences the oil reservoir properties so intensively that all oil components were changed by the injection. [ABSTRACT FROM PUBLISHER]

The purpose of this research was to study the effect of CO2injection on the geochemistry of crude oil in order to determine the probability of using geochemical parameters for monitoring CO2injection. In this process, four oil samples from different offshore oil fields were collected, synthetic steady state oil reservoir (porous media) were made by slim tube apparatus, then CO2injection process was done in different pressures. Various geochemical analyses were also carried out on the injected oil before and after the injection. The results show that the bulky changes on oil sample by CO2injection. CO2injection is more likely to precipitate complex and large molecules such as asphaltenes-resins and also large normal alkanes. In this case, the percentage of aromatic molecules was increased during injection. In general view on chromatograms, the height and abundance of all saturated compound peaks after CO2injection were significantly decreased. However, biomarker analysis shows that CO2injection has a tendency to change source and maturity biomarker parameters. [ABSTRACT FROM AUTHOR]

According to elemental analysis practiced on 47 samples from different locations in Persian Gulf, pelagic carbonate rocks constitute the dominant source rock while an increase is observed in amounts of evaporative facies in eastern regions and shale facies in southern regions. The isotope analysis reveals that there are three groups of source rocks in Persian Gulf; first are Asmari layers with an age of 95–97 million years, second is reservoir layer of Sarvak with an age of 105–107 million years estimated for its source rock, and third are numerous reservoir layers with source rock ages between 138 and 145 million years. [ABSTRACT FROM AUTHOR]

One of the standard methods of estimating the amount of hydrocarbon generated is determining the kinetic parameters of source rock samples. Therefore, three immature samples from well-known Iranian source rocks (Pabdeh, Gurpi, and Kazhdumi) artificially were matured by an open pyrolysis system (Rock-Eval 6) at temperature rates of 5 and 15°C/min in bulk. Optimization was done by Optkin software. Kinetic parameters (A, E) and amount of generated hydrocarbon was determined. The results show different kinetic parameters for each sample and significant differences between them and the global kinetic parameters. Consequently, to get an accurate kinetic model in a petroleum system, a strategy for determining kinetic parameters on any new source rock samples is proposed. [ABSTRACT FROM AUTHOR]

It is essential that precipitation of asphaltenes is recognized early in the planning stage of any CO2 enhanced oil recovery (EOR) project so that appropriate testing can be performed to evaluate whether there will be a negative impact on reservoir performance. This article presents detailed evaluations of slim tube data that were obtained during CO2 injection using a medium-gravity Iranian crude oil. A crude oil from Bangestan reservoir of Ahwaz oilfield containing 18.2% asphaltenes with ~31.5 °API gravity was flooded by purified CO2 (>96% CO2) in a slim tube apparatus under 2,700 psi at 110°C. We were going to determine the minimum miscibility pressure (MMP) of the sample oil under injection of CO2 flood, but when a CO2 slim tube test was performed for this oil at 2,700 psi, less than half of the saturated oil in the tube was recovered, which implied that the displacement process was immiscible. At this pressure, the asphaltene deposition in the slim tube apparatus was so severe that even a pressure gradient of 6,200 lb/in2 was not able to displace any fluid through the capillary tube. Therefore, we abandoned MMP determination with this sample and investigated the problem. Due to the high percentage of asphaltenes in the sample, using the slim tube MMP as an apparatus for determining minimum miscibility pressure of CO2 and sample oil can be misleading. [ABSTRACT FROM AUTHOR]

Due to the lack of information about the porosity exponent (m) from core experiments, the impossibility of comparison between the results and the core data, and, finally, inattentiveness to fractured intervals, the correct determination of the porosity exponent value in the calculation of water saturation and also the core-log correlation have generally been neglected. In this article, an analysis of the Mishrif Unit was carried out in two wells in order to properly calculate the water saturation and determine the best producing intervals. Based on fractured zones detection and the results of petrophysical evaluation in the calculation of shale volume and true matrix properties for these zones, accurate values of the porosity (matched with core data) were used to determine the porosity exponent. Hence, one of the advantages of this study is applying the method introduced simply for the fractured parts of the reservoir unit, in order to obtain the correct value for water saturation. Detecting proper producing intervals in the Mishrif Unit was executed using integrated evaluation of petrophysical data, geological data, and core data using a new method of shaly carbonate formation interpretation based on petrophysical log results. In this method, a statistical parameter, P½, was used. The results from the application of the method show better interpretation and water saturation calculation using petrophysical logs of fractured shaly carbonate formations in combination with other available methods in the petroleum community. [ABSTRACT FROM AUTHOR]

High-resolution (biomarker) geochemistry combined with other geochemical data has been used to investigate the genetic relationships of 14 crude oil samples from the Iranian sector of the Persian Gulf, and to provide information on the lithologies, palaeo-depositional environments and probable ages of the respective source rocks. Oil samples from the Resalat, Salman, Sirri A, Sirri C, Sirri D and Sirri E fields in the SE of the Gulf, and the Foroozan, Bahregansar, Hendijan, Abouzar, Doroud and Nowrouz fields in the NW of the Gulf were investigated. Results indicate that the studied oils belong to three genetic groups: (i) Group 1 oils (Resalat and Salman fields) were sourced from Jurassic or older, shaly source rocks deposited in a relatively oxic environment; (ii) Group 2 oils (Nowrouz, Doroud and Foroozan oilfields) originated from Jurassic or older carbonate-rich source rocks deposited in an anoxic environment; (iii) Group 3 oils, which, according to biomarker parameters, were probably sourced from Middle Cretaceous calcareous shales. Two subgroups are recognised: subgroup 3A oils were sampled from oilfields located in the NW of the Gulf (Hendijan, Bahregansar and Abouzar), and subgroup 3B oils came from the south (Sirri A, Sirri C, Sirri D and Sirri E fields). [ABSTRACT FROM AUTHOR]

Abstract: We present a non parametric Bayesian multiscale method to characterize the Hemodynamic Response HR as function of time. This is done by extending and adapting the Multigrid Priors (MGP) method proposed in (S.D.R. Amaral, S.R. Rabbani, N. Caticha, Multigrid prior for a Bayesian approach to fMRI, NeuroImage 23 (2004) 654–662; N. Caticha, S.D.R. Amaral, S.R. Rabbani, Multigrid Priors for fMRI time series analysis, AIP Conf. Proc. 735 (2004) 27–34). We choose an initial HR model and apply the MGP method to assign a posterior probability of activity for every pixel. This can be used to construct the map of activity. But it can also be used to construct the posterior averaged time series activity for different regions. This permits defining a new model which is only data-dependent. Now in turn it can be used as the model behind a new application of the MGP method to obtain another posterior probability of activity. The method converges in just a few iterations and is quite independent of the original HR model, as long as it contains some information of the activity/rest state of the patient. We apply this method of HR inference both to simulated and real data of blocks and event-related experiments. Receiver operating characteristic (ROC) curves are used to measure the number of errors with respect to a few hyperparameters. We also study the deterioration of the results for real data, under information loss. This is done by decreasing the signal to noise ratio and also by decreasing the number of images available for analysis and compare the robustness to other methods. [Copyright &y& Elsevier]

Abstract: Dry powders suitable for inhalation containing β-estradiol, leucine as a dispersibility enhancer and lactose as a bulking agent were prepared by spray-drying from aqueous ethanol formulations. The influence of formulation components on the characteristics of the resultant spray-dried powders was examined through the use of a range of ethanol concentrations (10–50% v/v) in the solvent used to prepare the initial formulations. Additionally, the amount of leucine required to act as a dispersibility enhancer was investigated by varying the amount of leucine added to the formulation prior to spray-drying. Following spray-drying, resultant powders were characterised using scanning electron microscopy, laser diffraction and tapped density measurements, and the aerosolisation performance determined using Twin Stage Impinger and Andersen Cascade Impactor analysis. We demonstrate that selection of appropriate solvent systems and leucine concentration allows the preparation of spray-dried powders that display enhanced aerosolisation properties, and would be predicted to exhibit high deposition in the lower regions of the respiratory tract. [Copyright &y& Elsevier]

We introduce multigrid priors to construct a Bayesian-inspired method to asses brain activity in functional magnetic resonance imaging (fMRI). A sequence of different scale grids is constructed over the image. Starting from the finest scale, coarse grain data variables are sequentially defined for each scale. Then we move back to finer scales, determining for each coarse scale a set of posterior probabilities. The posterior on a coarse scale is used as the prior for activity at the next finer scale. To test the method, we use a linear model with a given hemodynamic response function to construct the likelihood. We apply the method both to real and simulated data of a boxcar experiment. To measure the number of errors, we impose a decision to determine activity by setting a threshold on the posterior. Receiver operating characteristic (ROC) curves are used to study the dependence on threshold and on a few hyperparameters in the relation between specificity and sensitivity. We also study the deterioration of the results for real data, under information loss. This is done by decreasing the number of images in each period and also by decreasing the signal to noise ratio and compare the robustness to other methods. [Copyright &y& Elsevier]

The normal aging of the extracellular matrix and collagen content of the human lumbar intervertebral disc (IVD) remains relatively unknown despite vast amounts of basic science research, partly because of the use of inadequate surrogates for a truly normal, human IVD. Our objective in this study was to describe and compare the morphology and ultrastructure of lumbar IVDs in 2 groups of young (G1—<35 years) and elderly (G2—>65 years). Thirty L4-5 and L5-S1 discs per group were obtained during autopsies of presumably-asymptomatic individuals and analyzed with magnetic resonance imaging (MRI), a morphological grading scale, light microscopy, scanning electron microscopy (SEM) and immunohistochemistry (IHC) for collagen types I, II, III, IV, V, VI, IX and X. As expected, a mild to moderate degree of degeneration was present in G1 discs and significantly more advanced in G2. The extracellular matrix of G2 discs was significantly more compact with an increase of cartilaginous features such as large chondrocyte clusters. Elastic fibers were abundant in G1 specimens and their presence correlated more with age than with degeneration grade, being very rare in G2. SEM demonstrated persistence of basic structural characteristics such as denser lamellae with Sharpey-type insertions into the endplates despite advanced age or degeneration grades. Immunohistochemistry revealed type II collagen to be the most abundant type followed by collagen IV. All collagen types were detected in every disc sector except for type X collagen. Statistical analysis demonstrated a general decrease in collagen expression from G1 to G2 with an annular- and another nuclear-specific pattern. These results suggest modifications of IVD morphology do not differ between the anterior or posterior annulus but are more advanced or happen earlier in the posterior areas of the disc. This study finally describes the process of extracellular matrix modification during disc degeneration in an unselected, general population and demonstrates it is similar to the same process in the cervical spine as published previously. [ABSTRACT FROM AUTHOR]

This article is an experimental program that was undertaken to investigate miscible gas (methane) injection effect on oil composition during enhanced oil recovery process. In order to perform the injection operation and calculating minimum miscibility pressure, a slim-tube apparatus was used. After that, geochemical tests were employed to investigate the effect of methane injection on oil composition. A chosen oil sample (API 30.5) was taken from “B” field on the eastern side of the Persian Gulf. Although polar components have been affected by the methane injection in a way that asphaltenes and resins content were decreased after injection, non-polar compounds have not been changed at all. [ABSTRACT FROM PUBLISHER]

Foroozan field, with seven different reservoir layers, is one of the complex fields in the Persian Gulf. The purpose of this study was to identify intra-reservoir compartmentalisation using geochemical and reservoir engineering evidences. On the basis of this approach, 11 gaseous samples, which belong to different wells producing from the Burgan reservoir of Foroozan field, were selected. Gas composition, gas isotopes and associated oil bulk properties were tested to determine the reservoir continuity through the Burgan reservoir. In addition, fluid contacts and properties are also used to investigate reservoir continuity. Regarding clear differences in gas composition such as hydrogen sulphide concentrations, at least two separate segments in the north and south of the reservoir were detected. Moreover, the percentages of the different gas components indicated two separate compartments. Other evidences such as C 1 – C 4 alkane isotopic compositions and sulphur and nitrogen isotopic signatures confirmed the Burgan reservoir compartmentalisation. A number of petroleum bulk properties confirmed gradual variations that provide supplementary evidence on the reservoir-filling direction, signifying that fluids equilibrium had not been extended through the Burgan reservoir, laterally. Initial reservoir condition, different original water–oil contacts, solution gas–oil ratio at original pressure and bubble point pressure are other reservoir engineering evidences that support the Burgan reservoir compartmentalisation. [ABSTRACT FROM AUTHOR]

Purpose: An experimental model of in vivo cryoablation of the spine is unknown. The aim of this study is to describe the technical aspects of a image-guided percutaneous cryoablation of the spine in a swine model. Material and methods: Cone beam CT (CBCT)-guided percutaneous cryoablation was performed in five domestic female swines (14 lumbar vertebral bodies). A 1.7-mm cryoprobe was inserted by transpedicular route through 10 G vertebroplasty needles. Epidural thermosensor insertion and CO2 injection were provided to help preventing spinal cord or nerve injuries. Modified freeze-thaw-freeze cycles were delivered. Clinical observation of the models was carried out for 6days after ablation. Spine MRI was then performed before euthanasia followed by complete pathological analysis. Results: Good quality images of the spine canal CO2 distribution, as well as the needles inside vertebrae were obtained with CBCT . The five animals survived for their designated time of 6days after spine cryoablation; the lowest temperatures recorded at the center of the cryolesion and at the spine canal were respectively −121°C and 14°C; only one animal presented with foot flexion limitation; no significant symptoms were registered in the other four animals. Conclusion: This is the first report of an experimental image-guided percutaneous cryoablation of the spine in a swine model. The technique was feasible and good short-term clinical results were reported. Source of funding: FAPESP - Fundação de Amparo à Pesquisa do Estado de São Paulo. Conflict of interest: None declared. ricardomcfreitas@gmail.com [ABSTRACT FROM AUTHOR]